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INTERNAL: Service Bulletin: To inform field service of potential braze joint deterioration on FM35-50 and ACFM liquid cooled unit

INTERNAL ONLY

Issue:
Service Bulletin: To inform field service of potential braze joint deterioration on FM35-50 and ACFM liquid cooled unit

Product line:
Network Air FM, ACFMXXX, IR40

Environment:
All Serial Numbers

Cause:
A potential for braze joint deterioration to exist on copper to stainless steel, braze plate heat exchanger joints, on all liquid cooled FM and ACFM units. The cause may be due to certain compound levels in the water/glycol, sustained or maximum pressure of the loop, physical joint formation, or any combination of these conditions. A deteriorated joint will begin to weep liquid and eventually separate. Inspect these joints for signs of leaks or joint separation. If a leak or separation is found repair the joint,

Resolution:
The following inspection procedure should take approximately 15 minutes to perform. Repair will take approximately 6 hours. Inspect full perimeter of joint for signs of a leak or separation. A leak will be visible as wet areas, a build up of sediment, or both.There may be visible joint separation without the formation of a leak(Fig 1). Separation will be visible in the form of the brazed joint being pushed away from the stainless steel. This movement can be detected as visible gap between the braze fillet and the stainless steel surface (Fig. 2). Full separation can be seen in (Fig. 3). If any of the above conditions are present, the joint should be reformed. To reform the brazjoint, the existing joint needs to be fully removed, and re-brazed as if making a new joint.Reflowing the joint or adding more braze material over the existing joint, will not fix the issue. It may be easier to cut a portion of the piping off for joint removal and install a new stub and sleeve to make new joint. To avoid a potential over pressurization of the refrigerant circuit, due to the heat applied to the heat exchange during the brazing process. The refrigerant charge should br removed